Plot is not the same thing as stuff happening.
Stuff happening is life, and it's history (at least, history prior to interpretation). It may or may not have shape and pattern. It's one damn thing after another (quotes variously attributed to Henry Ford, Elbert Hubbard and Arnold Toynbee), whether or not those things are related, make sense or go anywhere.
Plot is different. Plot must have a shape and pattern. Plot is a character struggling against obstacles to achieve an objective and either succeeding or failing.
Does a book need to have a plot? No. It can be driven by character, milieu or something else. Some books, even famous, award-winning, best-selling books, have weak plots or even no plot at all.
Is any book better if it contains plot, as opposed to just one damn thing after another? Yes.
Must your novel have a plot? Yes, absolutely. Preferably more than one, interconnected and feeding into each other before the end.